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*                			For Vision Open Statistical Models											*
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* Copyright (C):	2006~2011 by JIA Pei, all rights reserved.											*
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*					1) P. JIA, 2D Statistical Models, Technical Report of Vision Open Working Group,	*
*					2st Edition, October 21, 2010. 														*
*					http://www.visionopen.com/members/jiapei/publications/pei_sm2dreport2010.pdf		*
* 					2) P. JIA. Audio-visual based HMI for an Intelligent Wheelchair. PhD thesis,		*
* 					University of Essex, February, 2011.												*
* 					http://www.visionopen.com/members/jiapei/publications/pei_phdthesis2010.pdf			*
*					3) T. Cootes and C. Taylor. Statistical models of appearance for computer vision.	*
*					Technical report, Imaging Science and Biomedical Engineering, University of 		*
*					Manchester, March 8, 2004.															*
*					http://www.isbe.man.ac.uk/~bim/Models/app_models.pdf								*
*					4) I. Matthews and S. Baker. Active appearance models revisited. International 		*
*					Journal of Computer Vision, 60(2):135–164, November 2004.							*
*					http://www.ri.cmu.edu/pub_files/pub4/matthews_iain_2004_2/matthews_iain_2004_2.pdf	*
*					5) M. B. Stegmann, Active Appearance Models: Theory, Extensions and Cases,			*
*					http://www2.imm.dtu.dk/~aam/main/, 2000												*
* 																										*
* Version:          0.3.2                                                     							*
* Author:           JIA Pei                                                 							*
* Contact:          jp4work@gmail.com                                       							*
* URL:              http://www.visionopen.com                               							*
* Create Date:      2010-11-04                                             								*
* Revise Date:      2010-08-04                                             								*
********************************************************************************************************/


#ifndef __VO_TRIANGLE2D_H__
#define __VO_TRIANGLE2D_H__

#include <vector>
#include "opencv/cv.h"
#include "opencv/highgui.h"
#include "VO_Shape.h"
#include "../utils/VO_Common.h"

using namespace std;
using namespace cv;


/** 
 * @author		JIA Pei
 * @brief		A shape specifically to describe a 2D triangle. 
 */
class VO_Triangle2D : public VO_Shape
{
protected:
    /** Cached denominator for later Jacobian calculation */
    float						m_dD;

    /** private function to calculate cached denominator */
    float 						Calc_dD()
    {
								if(this->m_MatShape.cols != 3)
									cerr << "This is not a triangle!" << endl
										<< "Please ensure the shape has 3 columns" << endl;
								if(this->m_MatShape.rows != 2)
									cerr << "This triangle is not in 2D!" << endl;

								float x1, x2, x3, y1, y2, y3;
	
								x1 = this->m_MatShape(0,0);
								x2 = this->m_MatShape(0,1);
								x3 = this->m_MatShape(0,2);
								y1 = this->m_MatShape(1,0);
								y2 = this->m_MatShape(1,1);
								y3 = this->m_MatShape(1,2);
	
								return (+x2*y3-x2*y1-x1*y3-x3*y2+x3*y1+x1*y2);
    }

public:
	enum { COUNTER_CLOCKWISE = 0, CLOCKWISE = 1};

    /** Default constructor to create a VO_Triangle2D object */
	VO_Triangle2D() 			{this->m_MatShape = Mat_<float>::zeros(2,3); this->m_dD = 0.0f;}

    /** Constructor to create a VO_Triangle2D object with three coordinate vertexes in vector format */
    VO_Triangle2D(const vector<Point2f>& iVertexes):VO_Shape(iVertexes)
    {
								if(this->m_MatShape.cols !=3)
									cerr << "This is not a triangle!" << endl;
								if(this->m_MatShape.rows !=2)
									cerr << "This triangle is not 2D!" << endl;
								this->m_dD 			= this->Calc_dD ();
	}
	
	/** Constructor to create a VO_Triangle2D object with three coordinate vertexes in Mat_<float> format */
    VO_Triangle2D(const Mat_<float>& iVertexes):VO_Shape(iVertexes)
    {
								if(this->m_MatShape.cols !=3)
									cerr << "This is not a triangle!" << endl;
								if(this->m_MatShape.rows !=2)
									cerr << "This triangle is not 2D!" << endl;
								this->m_dD	= this->Calc_dD ();
	}

    /** Destructor */
	virtual ~VO_Triangle2D()	{}
	
    /** operator= overloading, similar to copy constructor */
    VO_Triangle2D&      		operator=(const VO_Triangle2D& s)
    {
								this->CopyData(s);
								this->m_dD	= s.GetdD();
								return (*this);
    }

	/** whether the triangle vertexes are list in clockwise or counter-clockwise */
	int 						determinant( )
	{
								float determ = (this->m_MatShape(0,1) - this->m_MatShape(0,0)) 
											* (this->m_MatShape(1,2) - this->m_MatShape(1,0)) 
											- (this->m_MatShape(0,2) - this->m_MatShape(0,0)) 
											* (this->m_MatShape(1,1) - this->m_MatShape(1,0));
								if (determ <= 0.0)
									return COUNTER_CLOCKWISE;
								else
									return CLOCKWISE;
	}

    /** Get cached denominator of this triangle */
    float                   	GetdD() const { return this->m_dD;}

    /** Set cached denominator for this triangle */
    void                    	SetdD(float idD) { this->m_dD = idD;}
};

#endif  // __VO_TRIANGLE2D_H__

